Extreme Solar Activity
One of the most powerful solar flares in years, a remarkable X17-category explosion, erupted from giant sunspot 486 this morning at approximately 1110 UT and, as a result, a strong solar
radiation storm is in progress.
(Click here to learn about the effects of such storms.) The explosion hurled a coronal mass ejection (CME) directly toward Earth. When it left the sun, the cloud was traveling
2125 km/s (almost 5 million mph). This CME could trigger bright auroras when it sweeps past our planet perhaps as early
as tonight.
Above: This SOHO coronagraph image captured at 12:18 UT shows the coronal mass ejection of Oct. 28th billowing directly toward
Earth. Such clouds are called halo CMEs. The many speckles are solar protons striking the coronagraph's CCD camera. See the complete movie.
Where will the auroras appear?
High-latitude sites such as New Zealand, Scandinavia, Alaska, Canada and US northern border states from Maine to
Washington are favored, as usual, but auroras could descend to lower latitudes when the CME described above sweeps past
Earth.
Not all CMEs trigger auroras. Several, for instance, have swept past Earth in recent days without causing widespread
displays. It all depends on the orientation of tangled magnetic fields within the electrified cloud of gas. The incoming
CME is no exception. It might cause auroras, or it might not. We will find out when it arrives.